Ammonia pump



United States Patent GHice 3,521,794 Patented July 28, 1970 3,521,794AMMONIA PUMP Dingeman Bijl, Rotterdam, Netherlands, assignor to GAFCorporation, New York, N.Y., a corporation of Delaware Filed Aug. 1,1967, Ser. No. 657,603 Int. Cl. G01f 1.7/06

U.S. Cl. 222-309 7 Claims ABSTRACT OF THE DISCLOSURE This inventionrelates to an electromagnetic pump for supplying an intermittentquantity of liquid ammonia to a diazo developing machine. The pumpinclu-des a slidable piston adapted to be actuated by the armature of anelectromagnet. The coil of the electromagnet is intermittently energizedsolely by a capacitor discharge circuit responsive to a selectivemicroswitch, the latter of which is controlled by operation of thedeveloping machine.

This invention relates to electromagnetic pumps and, in particular, toan improved electromagnetic ammonia pump for periodically dispensingpredetermined quantities of liquid ammonia from a container.

In the use of various categories of diazo-type developing machines, itfrequently becomes necessary to meter predetermined amounts of liquidammonia into the developer chambers. The quantities of liquid ammoniarequired depend essentially on the feed rate of diazo material beingprocessed in the developer chambers of the machines during a giveninterval or unit of time. As a result, the flow of ammonia into thedeveloping chambers of the diazo developing machines must be metered rcontrolled in dependence upon the feed rate of the diazo material. Otherfactors which alect the amount of ammonia liquid which must be suppliedto the developer chambers are the varied developing conditions demandedby different types of diazo materials. This, in effect, required thedevelopment of pumps and pumping systems which convey the liquid ammoniafrom a container directly into the developing chamber portions of thedeveloping machines.

Recently, in order to overcome the handling problems encountered withthe use of liquid ammonia, pumps have been developed which periodicallypump or convey quantities of liquid ammonia from containers into thedeveloping machines. Although the prior art pumps have been found to begenerally satisfactory when employed under ordinary or normal workingconditions, problems have been encountered at various times. Thus, forexample, the tendency of liquid ammonia to vaporize. at somewhatelevated temperatures under pump pressure conditions, has causedvapor-lock in the ammonia pumps, resulting in failure to providesuilicient liquid ammonia to the developing machines.

The novel and improved electromagnetic liquid ammonia pump according tothe present invention, overcomes the foregoing and other disadvantagesencountered in the prior art, by providing a pump which avoids vaporlockof the liquid ammonia, and which will assure an adequate supply ofammonia to the developing machine in response to a machine actuatedelectrical circuit energizing the pump. In effect, the present pumpincorporates an electromagnetic coil which is periodically energizedthrough a charged capacitor, by the operation of the developing machine.As a result of the coil energization, a magnetic armature which isslidably positioned within the pump will be actuated and in turn impartfluid-pumping motion to a piston member so as to `dispense liquidammonia from a container to the diazo developing machine.

Accordingly, it is a primary object of the present invention to providean improved and novel electromagnetic pump for supplying liquid ammoniato a diazo-type developing machine.

Another object of the present invention is to provide an electromagneticliquid ammonia pump responsive to a charged capacitor which periodicallyenergizes the elec tromagnetic coil of the pump for predeterminedintermittent liquid ammonia feed.

A further and more specific object of the present invention is toprovide a novel and improved variable displacement electromagnetic pumpwhich is energized by a capactiance electrical circuit, and which isadapted to periodically convey predetermined quantities of liquidammonia from a container to a diazo developing machine.

These and other objects and many of the. attendant advantages of thisinvention will be readily appreciated as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawing in which there isshown a sectional view of an electromagnetic liquid ammonia pump and aschematic view of the electrical circuit for operating theelectromagnetic pump in ac cordance with the present invention.

Referring now to the drawing, there is illustrated an electromagneticammonia pump assembly generally designated by reference numeral 1. Thepump assembly 1 includes an elongate tubular member 2 formed of anonferro-magnetic material, such as thermoplastic. The bottom portion ofthe tubular member 2 may be crimped inwardly as shown at 3, so as toprovide clamping support for an internal piston sleeve 4. At the lowerend of piston sleeve 4, a hollow stainless steel plug 5 which is lockedthereto by a pin 6, seals the bottom of tubular member 2. The bottomwall 7 of plug 5 includes an aperture 8 for the passage of liquidammonia. Internally of plug 5, wall 7 provides for a valve seat 9adapted to support and seat a stainless steei check ball valve 10.

In the region of the upper end of tubular member 2, an electromagneticcoil assembly or solenoid generally designated by reference numeral 11encompasses the tubular member 2 and is fastened thereto. The coilassembly 11 is encased in a suitable plastic housing 12 which providesaccess for an electrical conduit 13 adapted to connect the coil assemblywith an electrical circuit generally designated by reference numeral 14.The lower end of plastic housing 12 may include sealing surfaces 15which cooperate in sealing relationship with a cork or stopper 16 of anammonia supply container 17.

Interiorly of tubular member 2, and in loosely tting relationshiptherewith, a generally cylindrical ferroemagnetic armature core 18 ispositioned so as to be slidable along the longitudinal axis of thetubular member 2. Armature core 18 is connected by means of an elongatedWire 19 to a hollow piston 20. Piston 20, which may be formed ofstainless steel, is loosely slidable along the longitudinal axis oftubular member 2, and is supported by internal piston sleeve 4. Theupper portion of piston 20 and the lower end of armature core 1S mayhave steel cross-pins extending therethrough, about which the ends ofconnecting wire 19 may be wound.

Piston 20 includes a bottom wall portion 21 which is adapted to besupported on steel plug 5 when the piston is in its lowermost positionin tubular member 2. Bottom wall portion 21 includes an aperture 22 forthe passage of liquid ammonia. The inner surface of wall portion 21provides for a valve seal 23 adapted to seat a stainless steel ballcheck valve 24.

At the upper end of tubular member 2, the latter may include internalthreads adapted to cooperatively engage the threads of a hollow setscrew 25 -which may be manually threaded into or out of the tubularmember 2 and thereby determine the displacement of the piston.

The electrical circuit 14 for the pump assembly 1, includes a source ofelectrical power 26. A suitable resistor 27, diode 28, and capacitor 29are connected in series to the source of power 26, across a single-poletwo-way switch 30. In parallel relationship with capacitor 29, relativeto electrical power source 26, is the electromagnetic coil assembly 11of the pump 1.

In order to place the pump assembly 1 into operation, it is insertedinto supply container 17 which contains a quantity of liquid ammonia.The lower portion of tubular member 2 extends down into the liquidammonia, while the upper end thereof may have a suitable conduit (notshown) attached thereto for conveying pumped liquid ammonia to adeveloping machine under a pressure head which normally fills thetubular member 2. with ammonia.

4Electrical power source 26 charges capacitor 29, since switch 30 isnormally in contact with contact point 30a. This, in effect, will leaveelectromagnetic coil 11 in a deenergized condition. Switch 30, however,may be a microswitch which is adapted to be actuated by a cam (notshown) attached to a rotating member of the developing machine. Thus,when the cam on the developing machine actuates microswitch 30 so as tomove it to contact point 30h, the capacitor 29 is discharged acrosselectromagnetic coil assembly 11. As a result, armature core 18 will beinstantaneously displaced upwardly until stopped by set screw 25. Sincehollow piston 20 will move with armature core 18, by virtue of beingfastened thereto, a quantity of liquid ammonia in the upper portion oftubular member 2 will be forced through the hollow set screw 25 into thedeveloping machine. The amount of ammonia conveyed into the developingmachine is proportional to the displacement stroke of the armature core18.

The energization of electromagnetic coil 11, and the resulting upwardmotion of hollow piston 20, will create a region of reduced pressurebelow bottom wall 21 of the piston 20, and above the plug 5.Consequently, liquid ammonia from container 17 will raise ball checkvalve off its valve seat 9 and enter the space below the raised bottomsurface of piston 20.

As the cam portion of the developing machine, which controls microswitch30, continues to rotate, the microswitch contact will return to contactpoint 30a. This, in effect, de-energized electromagnetic coil 11 byopening the circuit to capacitor 29. Simultaneously, return ofmicroswitch 30 to contact point 30a will facilitate recharging of thecapacitor 29 by electrical power source 26. Deenergization ofelectromagnetic coil 11 causes armature core 18 and hollow piston 20 todescend by gravity within tubular member 2. The descent of piston willcause the liquid ammonia which has collected below, as a result oflifting of ball check valve 10, to raise ball check valve 24 off itsseat. This will permit liquid ammonia to pass through aperture 22 andallow the piston 20` to settle down on the sur-face of plug 5. After thepiston 20 has completed its downward descent, and tubular member 2 isfilled with liquid ammonia from container 17, ball check valve 24 willreseat itself and close aperture 22 under the influence of gravitationalforces.

The aforedescribed operating cycle of the electromagnetic ammonia pumpis then repeated each time microswitch 30 is moved between contactpoints 30a and 30h resulting from operation of the developing machineand rotation of the control cam on the machine.

Since the pumping action of the electromagnetic pump assemb'ly 1 iscontrolled by the charge in the capacitor 29, which energizeselectromagnetic coil 11, low frequency of operation does not impair theefficiency of the pump as in prior art constructions, inasmuch as thespeed of piston 20 is governed solely by the energization of thearmature core 1-8.

Another aspect of the present pump construction is 4 that it permitssome deflection of tubular member 2 during operation without detrimentaleffect on the action of the pump.

Although the electromagnetic pump assembly has been described withreference to Ibeing actuated by a microswitch 30 controlled through acam on the developing machine, it becomes apparent that for moresophisticated installations, electric motors, which are driven insynchronous speeds with the developing machines, may be employed.

It should also be understood that the foregoing relates to only apreferred embodiment of the invention, and that it is intended to coverall changes and modifications of the example of the invention hereinchosen for the purposes of the disclosure, which do not constitutedepartures from the spirit and scope of the invention.

What is claimed is:

1. An electromagnetic pump for dispensing liquid from a bottle-neckedcontainer having a discharge opening in the neck thereof, comprising:

a vertical elongate tube having its lower end portion extending intosaid container through said discharge opening in such neck, said tubeincluding valve means at its lower extremity,

a hollow piston vertically slidable within said tube, said pistonincluding valve means at its lower extremity,

a coil encompassing said vertical tube only about its upper portionexteriorly of and above said container neck,

a vertical armature slidably disposed within said vertical tube in theregion of said coil, a vertical link loosely interconnecting saidarmature and said hollow piston in each tube, said armature and pistonbeing free to fall vertically downwardly under the sole iniiuence ofgravity when said coil is deenergized, and

electrical circuit means including capacitance storage discharge meansfor energizing said coil, whereby during such energization and solely inresponse to such discharge, said vertical armature and said hollowpiston are lifted upwardly so as to dispense liquid material from thetop of said tube.

2. An electromagnetic pump as defined in claim 1, wherein the upperdistal end of said tube includes means for adjustably limiting theupward displacement of said hollow piston. Y

3. An electromagnetic pump as defined in claim 2, wherein saiddisplacement limiting means comprises a hollow set screw threaded intothe upper end portion of said tube.

4. An electromagnetic pump as defined in claim 1, wherein said meanslink-connecting said armature and said hollow piston comprises a lengthof wire located within the tubular member.

5. An electromagnetic pump as defined in claim 1, wherein saidelectrical circuit means comprises:

a source of electrical current, and

a capacitor adapted to be charged by said source of electrical current,when said coil is deenergized,

said circuit means including a selectively operable single-pole two-waymicroswitch for connecting said capacitor to said source of electricalcurrent to charge the capacitor while concurrently maintaining said coilin a deenergized condition, and means for periodically operating saidmicroswitch whereby said charged capacitor means is discharged acrosssaid coil so as solely to energize the latter to raise the armature linkand piston through a single fluid pumping stroke thereof.

6. The invention as defined by claim 5, in which said pump is secured inthe container by a stopper fitting the container opening,

said stopper having a vertical hole the wall of which fits said tubularmember and holds the pump in an upright position in the container.

7. The invention as dened by claim 6, in which said 0 coil is locateddirectly above said stopper and the container.

References Cited UNITED STATES PATENTS Smith 222-333 X Strobell 222-333X A'bbott 222-333 X Lopater 222-385 X Dunning et al. 3'18-130 X McDowallet a1 222-309 6 Wallace 103-53 XR Parker 103-53 Ray 103-53 XR Kofnk103-53 5 ROBERT B. yREEVES, Primary Examiner HODD S. |LANE, AssistantExaminer U.S. C1. X.R.

10 10s-53, 211; 222-333, 385; 31a-13o

